<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        #box{
            position: relative;
            width: 100vw;
            height: 100vh;
            background-color: gray;
        }
        .circle{
            position: absolute;
            border-radius: 50%;
        }
    </style>
</head>
<body>
<div>
    <button id="btnCircle">随机生成圆形</button>
    <div id="box"></div>
</div>
<script src="createGraph.js"></script>
</body>
</html>